1. Field of the Invention
This invention relates to automotive clutch release mechanisms, and particularly to a lubricant sealing system for a self-aligning clutch release bearing.
2. Description of Prior Developments
In certain manual transmissions for automotive vehicles, a clutch release mechanism is provided to enable shifting from one gear ratio to another. Commonly, such a clutch release mechanism includes an annular carrier for an anti-friction bearing that is in selective pressure contact with an annular clutch disc. Typically, the clutch disc has a plurality of resilient fingers engaged with the anti-friction bearing so that axial motion of the bearing exerts pressure on the resilient fingers to release and disengage the clutch.
The annular carrier for the anti-friction bearing is supported on a stationary guide shaft so that an axial force on the carrier produces the desired axial motion of the anti-friction bearing. The axial force is provided by a pivotable yoke that is operably connected to a clutch pedal.
Commonly, the anti-friction bearing is mounted on the carrier so as to be radially adjustable or shiftable to compensate for misalignments that can occur between the clutch disc and the carrier axis. Pressure contact between the clutch disc and the anti-friction bearing causes one race of the bearing to be effectively locked to the clutch disc. The bearing can thereby rotate with the clutch disc while being slightly eccentric relative to the carrier, assuming some radial misalignment between the carrier and the clutch.
In some clutch release mechanisms, an axially acting spring is positioned between the carrier and one race of the anti-friction bearing. The spring provides an axial preload force that eliminates axial play between the bearing and the carrier while still permitting the bearing to shift radially to compensate for misalignments between the carrier and the clutch disc.
Also, in many clutch release mechanisms, a sealing system is provided for trapping lubricant within the annular space occupied by the anti-friction elements, i.e. the balls or rollers. The trapped lubricant reduces the coefficient of friction and also transfers heat from the friction surfaces thereby increasing the service life of the bearing. In some cases, the sealing system has failed due to the failure of a radial lip seal to maintain sealing contact between the inner and outer races of the bearing.